Peripheral
administration of monosodium glutamate (MSG) stimulates feeding in rodents.
This may be due to the direct activation of glutamate receptors expressed in
the arcuate nucleus (ARC) of the hypothalamus. We have used manganese
enhanced MRI (MEMRI) to demonstrate that intraperitoneal administration of
MSG dose dependently increases Mn2+ influx into the ARC and that this can be
suppressed with a glutamate receptor subtype specific receptor antagonist.
These results reveal that MEMRI is a sufficiently sensitive tool to detect
glutamatergic signalling in vivo with high temporal and spatial resolution.